How high of a fever prompts a hospital visit when pregnant? I'm currently at 99.6

ADDED NOTE: I understand that 99.6 isn't really a fever. That's not my concern. I was 97 earlier today and as the day has progressed it has gone up so I was just looking for advice as to when I should be concerned since I'll be monitoring this through the night and when I should go to the hospital if it progresses. I just want to know what number would be considered dangerous while pregnant